It is known to manufacture complex three-dimensional work pieces by selectively exposing powder layers to electromagnetic radiation or particle radiation. In such manufacturing approaches, a raw material powder layer of a metallic or a ceramic material is deposited onto a carrier. Then, the raw material powder layer is selectively exposed to irradiation (e.g. to a laser beam). The positions of the powder areas selectively exposed to irradiation usually differ from raw material powder layer to raw material powder layer and depend on a target geometry of the three-dimensional work piece to be manufactured. Due to the irradiation, particles of raw material powder located within the irradiated areas melt or sinter, thereby transforming the parts of the raw material powder layer located within the irradiated areas into corresponding solid material structures. After having generated the solid material structures, a further raw material powder layer is deposited onto the carrier (i.e. deposited onto the overall solid material structure generated so far), and is exposed to irradiation in corresponding selected areas, and so on.
FIG. 1 schematically shows a conventional powder application apparatus 10. The powder application apparatus 10 comprises a powder storage 12 provided in a first part of the powder application apparatus and configured to receive and store raw material powder. Further, the powder application apparatus 10 comprises a powder supply channel 14 provided in a second part of the powder application apparatus 10 and configured to discharge raw material powder from the powder storage 12 onto a carrier 16 located below the powder application apparatus 10. A channel opening/closing mechanism 18 which is provided in the powder supply channel 14 comprises a moving element configured to be moved between a first position in which the moving element allows the discharge of raw material powder from the powder storage 12 onto the carrier 16, and a second position in which the moving element prevents the discharge of raw material powder from the powder storage 12 onto the carrier 16. The channel opening/closing mechanism 18 usually comprises electric motors which drive the moving element between the first and the second position.